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Domestic sheep and their wild relatives harbor substantial genetic variants that can form the backbone of molecular breeding, but their genome landscapes remain understudied. Here, we present a comprehensive genome resource for wild ovine species, landraces and improved breeds of domestic sheep, comprising high-coverage (â¼16.10×) whole genomes of 810 samples from 7 wild species and 158 diverse domestic populations. We detected, in total, â¼121.2 million single nucleotide polymorphisms, â¼61 million of which are novel. Some display significant (P < 0.001) differences in frequency between wild and domestic species, or are private to continent-wide or individual sheep populations. Retained or introgressed wild gene variants in domestic populations have contributed to local adaptation, such as the variation in the HBB associated with plateau adaptation. We identified novel and previously reported targets of selection on morphological and agronomic traits such as stature, horn, tail configuration, and wool fineness. We explored the genetic basis of wool fineness and unveiled a novel mutation (chr25: T7,068,586C) in the 3'-UTR of IRF2BP2 as plausible causal variant for fleece fiber diameter. We reconstructed prehistorical migrations from the Near Eastern domestication center to South-and-Southeast Asia and found two main waves of migrations across the Eurasian Steppe and the Iranian Plateau in the Early and Late Bronze Ages. Our findings refine our understanding of genome variation as shaped by continental migrations, introgression, adaptation, and selection of sheep.
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Genoma , Oveja Doméstica , Animales , Asia , Europa (Continente) , Variación Genética , Irán , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADN , Ovinos/genética , Oveja Doméstica/genéticaRESUMEN
Isoquinoline alkaloid displays significant anti-gastric cancer effects due to its unique structure, which is attracting more and more attention for the development of anti-gastric cancer drugs. In this study, we explore the active components against gastric cancer from the Tibetan Medicine Corydalis hendersonii Hemsl, which is rich in isoquinoline alkaloids. 14 compounds including 2 previously undescribed natural products were obtained. Interestingly, an new active compound displays potent anti-gastric cancer activity. After accomplishing the total syntheses of the active compound and its derivatives, the anti-gastric cancer activity of the active compound was further investigated. In vitro experiments revealed that the active compound significantly attenuated the proliferative capacity, caused G2/M phase arrest, inhibited the cell migration and invasion, and induced cell apoptosis. Mechanistically, the active compound could increase the Bax/Bcl-2 ratio, elevate cytochrome c in the cytosol, and activate caspase-9/3, along with inactivating the upstream PI3K/Akt/mTOR signaling pathway. In addition, the active compound could also cause gastric cancer cell death by inhibiting topoisomerase I activity. More importantly, the anti-gastric cancer activity of the active compound was confirmed in MGC-803 xenograft nude mice in vivo. This work not only promotes the exploitation of Corydalis hendersonii Hemsl., but also provides some experience for discovering new entities from natural sources.
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Alcaloides , Corydalis , Neoplasias Gástricas , Alcaloides/química , Alcaloides/farmacología , Alcaloides/uso terapéutico , Animales , Apoptosis , Corydalis/química , Humanos , Isoquinolinas/química , Isoquinolinas/farmacología , Isoquinolinas/uso terapéutico , Ratones , Ratones Desnudos , Fosfatidilinositol 3-Quinasas , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/metabolismoRESUMEN
RNase E, a central component involved in bacterial RNA metabolism, usually has a highly conserved N-terminal catalytic domain but an extremely divergent C-terminal domain. While the C-terminal domain of RNase E in Escherichia coli recruits other components to form an RNA degradation complex, it is unknown if a similar function can be found for RNase E in other organisms due to the divergent feature of this domain. Here, we provide evidence showing that RNase E forms a complex with another essential ribonuclease-the polynucleotide phosphorylase (PNPase)-in cyanobacteria, a group of ecologically important and phylogenetically ancient organisms. Sequence alignment for all cyanobacterial RNase E proteins revealed several conserved and variable subregions in their noncatalytic domains. One such subregion, an extremely conserved nonapeptide (RRRRRRSSA) located near the very end of RNase E, serves as the PNPase recognition site in both the filamentous cyanobacterium Anabaena PCC7120 and the unicellular cyanobacterium Synechocystis PCC6803. These results indicate that RNase E and PNPase form a ribonuclease complex via a common mechanism in cyanobacteria. The PNPase-recognition motif in cyanobacterial RNase E is distinct from those previously identified in Proteobacteria, implying a mechanism of coevolution for PNPase and RNase E in different organisms.
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Cianobacterias/metabolismo , Endorribonucleasas/metabolismo , Oligopéptidos/metabolismo , Polirribonucleótido Nucleotidiltransferasa/metabolismo , ARN Bacteriano/genética , Secuencia de Aminoácidos , Dominio Catalítico , Biología Computacional , Cianobacterias/genética , Cianobacterias/crecimiento & desarrollo , Endorribonucleasas/genética , Immunoblotting , Datos de Secuencia Molecular , Polirribonucleótido Nucleotidiltransferasa/genética , ARN Bacteriano/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homología de Secuencia de Aminoácido , Técnicas del Sistema de Dos HíbridosRESUMEN
The balancers of Drosophila melanogaster are widely used in genetic research. By analyzing the phenotype of offspring from hybridization of chapped wing (L) mating with OR, 982p and e, respectively, we mapped the chapped wing mutation on chromosome 3 for the first time and demonstrated the chapped wing mutation as a new balancer of D. melanogaster with dominant wing nicking phenotype. Finally, we bred a novel gathering line with double balancers of L and Cy in D. melanogaster. The mutant L provided a legible dominant marker for the balancer of chromosome 3, and the cultivation of double balancers chapped-curly wing enriches the balancer stock, which is often used in mapping and screening.
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Mapeo Cromosómico , Cromosomas de Insectos , Drosophila melanogaster/genética , Alas de Animales/anatomía & histología , Animales , MutaciónRESUMEN
Seven single nucleotide polymorphisms (SNPs) were identified by PCR-SSCP and sequencing in the chicken apoA5 gene in F2 chickens from an experimental cross of White Plymouth Rock x Silkies. One SNP(C-169T) located on the 5'-regulatory region, another two in the second exon were transitions of C to T (600) and T to C (635). Four SNPs in the third exon were found, which were C841G, C914T, C1142G, C1394T. The association of the polymorphisms with carcass traits was investigated. The most significant results were yielded from primer apoA3F/R: the abdominal fat weight of CC chickens were significantly higher than that of AA, AB, AC, BB and BC chickens (P<0.05); AC chickens had lower liver weight than that of AA, AB, BB, BC and CC (P<0.05); BC chickens had lower heart weight than that of BB (P<0.05).
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Apolipoproteínas A/genética , Pollos/genética , Polimorfismo de Nucleótido Simple/genética , Grasa Abdominal/metabolismo , Animales , Tamaño de los Órganos/genética , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-Simple/genéticaRESUMEN
@#Abstract: Objective To analyze the distribution characteristics of the main pathogens of HIV/AIDS patients with wound infections and provide basis for clinical diagnosis and treatment. Methods The clinical data of 294 patients with positive secretions or pus specimens from 2016 to 2020 were analyzed retrospectively. Results A total of 357 strains of pathogenic bacteria were isolated from 294 cases, of which 123 strains of Gram-negative bacilli (G-b), accounting for 34.5%, were mainly Escherichia coli (15.4%), Klebsiella pneumoniae (3.9%), and Pseudomonas aeruginosa (3.6%); Gram-positive bacilli (G+b) 14 strains, accounting for 3.9%; 108 Gram-positive cocci (G+c), accounting for 30.3%, of which 44 strains were coagulase-positive Staphylococcus aureus (12.3%), Coagulase-negative staphylococci were mainly Staphylococcus epidermidis (4.2%) and Staphylococcus hemolyticus (2.8%); 37 strains of fungi, accounting for 10.4%, were mainly Candida albicans (5.9%); 75 strains of Mycobacterium, accounting for 21.0%, including 41 strains of Mycobacterium tuberculosis (11.5%) and 34 strains of non-tuberculosis mycobacteria (9.5%). 52 of the 294 HIV/AIDS patients had mixed infections, accounting for 17.7%. There was significant difference in the distribution of G+c, G-b, mycobacteria and mixed infection among different specimen sources (P<0.05), and there was significant difference in the distribution of mycobacteria among different CD4+T lymphocyte counts (P<0.05). There was significant difference in the level of CD4+T lymphocytes between patients of different ages (P<0.05), and there was significant difference in the level of CD4+T lymphocytes from postoperative incision and other parts (P<0.05). Conclusions Patients with HIV/AIDS are prone to combined wound infections with various pathogenic bacteria. We should strengthen the research on wound infection in HIV/AIDS patients, and timely send patients with a low number of CD4+T lymphocytes for secretion or pus culture, so as to carry out targeted treatment and improve the prognosis of patients.
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Polydactyly is a common malformation of vertebrate limbs. Preaxial polydactyly (PPD) has been mapped in human, mouse and chicken to the syntenic region of human 7q36. Lmbr1 was thought as the critical candidate gene for human and mouse PPD. To understand the molecular mechanism underlying chicken polydactyly, we have cloned the open reading frame (ORF) of chicken Lmbr1, which contains 1467 nucleotides. Within this ORF, we found one short and one long splice forms. The short splice form has a complete deletion of exon 4. Six cSNPs were found in the chicken ORF, and two of these cSNPs, G797A and G1255A, lead to amino acid substitutions. However, G797A substitution had no significant association with polydactyly and the G1255A substitution had very low frequency in the population. The T1254C polymorphism in exon 13 was found to be strongly associated with polydactyly. Radiation hybrid mapping of a DNA fragment containing intron 13 of the chicken Lmbr1 assigned the gene to chromosome 2 between MCW071 (a marker within the EN2 gene) and ADL0270, a syntenic region to human 7q36.
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Pollos/genética , Polidactilia/genética , Polimorfismo de Nucleótido Simple , Alelos , Empalme Alternativo , Sustitución de Aminoácidos , Animales , Secuencia de Bases , Cromosomas , Clonación Molecular , Exones , Ligamiento Genético , Intrones , Proteínas de la Membrana/genética , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Polidactilia/etiología , Polimorfismo Conformacional Retorcido-Simple , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Mapeo de Híbrido por RadiaciónRESUMEN
Curly is a easily distinguishable dominant mutant wing character. The Cy mutation is the most commonly used dominant marker for the second chromosome balancers in Drosophila melanogaster, but little is known about the Cy gene. Based on known genomic and cytogenetic information, a 102 bp deletion which is located between the Genes synaptotagmin (syt) and Activin Like Protein at 23B(Alp23B) on the Drosophila melanogaster genome (release 4) had been found to be commonly contained on Cy chromosome in three different curly strains. Meanwhile, when using the deletion as a DNA marker, the result suggested that Cy homozygote be lethal in embryo period. These results will provide some helpful information to investigate molecular mechanism of curly wings in the further study.
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Drosophila melanogaster/anatomía & histología , Drosophila melanogaster/genética , Genes de Insecto/genética , Eliminación de Secuencia , Alas de Animales/anatomía & histología , Animales , Secuencia de Bases , Cromosomas/genética , Drosophila melanogaster/crecimiento & desarrollo , Genotipo , Homocigoto , Alas de Animales/crecimiento & desarrolloRESUMEN
OBJECTIVE: To explore the cardiac function of left and right ventricles in children with bronchial asthma at the acute stage and its association with the disease severity. METHODS: The cardiac function was evaluated by using the American Acuson 128XP/10 Doppler echocardiography in 24 children with acute severe bronchial asthma and 40 children with acute mild bronchial asthma. Thirty-four healthy children were used as normal controls. RESULTS: The injury of right ventricle diastolic function was predominant in children with mild asthma, and the right ventricle systolic function was also decreased. The systolic and diastolic function of left ventricle remained normal. In children with severe bronchial asthma, the injury of left ventricle systolic function was commonly seen, and the left ventricle diastolic function and the right ventricle systolic and diastolic function were also damaged. CONCLUSIONS: The cardiac function damage occurs in children with acute bronchial asthma and may be correlated with the disease severity.
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Asma/fisiopatología , Corazón/fisiopatología , Niño , Preescolar , Ecocardiografía Doppler , Femenino , Humanos , Lactante , Masculino , Función Ventricular Izquierda , Función Ventricular DerechaRESUMEN
Soil enzymes involved in the conversion of soil carbon and nitrogen, meanwhile the availability of soil carbon and nitrogen is the base of soil enzymes, yet atmospheric N deposition influences the release of soil CO2 by reduce the activities of soil enzyme. The objective of this study was to investigate the effect of different nitrogen deposition on soil respiration and soil enzymes, and explore the relationship among soil respiration, soil temperature, soil moisture and soil enzymes in the Masson pine forest. The results might provide a reference for further study on the effects of nitrogen deposition on pine forest ecosystem. From May 2014 to July 2015, three nitrogen application treatments and a control treatment were set up: low nitrogen [N5, 20 g·(m2·a)-1], moderate nitrogen [N10, 40 g·(m2·a)-1], high nitrogen [N15, 60 g·(m2·a)-1] and control treatment [N0, 0 g·(m2·a)-1) in the Masson pine forest. We measured soil respiration, soil temperature, and soil moisture simultaneously by using the Automated Soil CO2 Exchange Station (ACE, UK). The results showed that: 1 Soil enzymes and soil respiration had obvious seasonal variation, soil respiration of N0, N5, N10 and N15 was the highest in Summer, followed by the Spring and Autumn, and the lowest in Winter, and no consistent change rule was found in soil enzymes. 2 Generally, nitrogen deposition suppressed soil respiration and soil enzymes, and these inhibitory effects were strengthened with increasing levels of nitrogen deposition. The only exception in which nitrogen deposition enhanced soil respiration was in the Masson pine forest in Winter, In Spring, Summer and Autumn, nitrogen deposition suppressed soil enzymes, while there was difference among Ure, Ive, CAT and ACP in Winter. 3 stepwise regression showed that in control treatment and low nitrogen treatment, T, Ure and Ive made great contributions to the Rs, and Rs rapidly increased with the increase of T, Ure and Ive. In middle nitrogen treatment, T, Ure and CAT made great contributions to the Rs, and Rs increased with the increase of T, Ure and CAT. In high nitrogen treatment, Rs decreased with the increase of Ure, yet Rs increased with the increase of CAT and W.
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Enzimas/química , Bosques , Nitrógeno/química , Estaciones del Año , Microbiología del Suelo , Suelo/química , China , PinusRESUMEN
The classical White (I) locus is one of the important pig coat color hereditable loci,which is homologous to KIT gene. In this study,PCR-RFLP and PCR-SSCP analysis were commanded on the Intron 17 and 18 nucleotide sequences of KIT gene. The tested results showed that the substitution mutation (G-->A) of Intron 17 was found in white pigs, including Wuzhishan pigs (white), Landrace and Large White,and its genotype (AB) frequency was 1.1 and 0.8 respectively. The genotype frequency was uniformly 0 in the other native pig breeds. Similarly,the deleted mutation (AGTT) of Intron 18 was also found in the same white pigs,its genotype (,AA) frequency was 1.1 and 0.93 separately,while in the other native pig breeds was 0. Accordingly it was considered that KIT gene was an important factor regulating the white coat color genotype, and the classical I locus (KIT gene) was epistatic to the other genetic coat color loci. On the other hand,although the native pig breed Rongchang Pig is similar to Landrace and Large White in phenotype (white coat color), the mutation status found in them was absolutely distinct. So it is presumed that the coat color genetic system of Chinese native pig breeds was different from that of imported breeds.
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Color del Cabello/genética , Mutación Puntual , Proteínas Proto-Oncogénicas c-kit/genética , Eliminación de Secuencia , Porcinos/genética , Animales , Secuencia de Bases , Cruzamiento , China , Análisis Mutacional de ADN , Femenino , Intrones , Masculino , Datos de Secuencia Molecular , Fenotipo , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo de Longitud del Fragmento de Restricción , Polimorfismo Conformacional Retorcido-Simple , Especificidad de la EspecieRESUMEN
With ESTs from porcine fatty tissue and cDNA sequences from human, bovine and mouse in non-reduncdant database and dbEST in GenBank,we sampled cDNA sequences of 70 function-known genes in four species on the base of randomly sampling method, analyzed the mutation pattern of 70 x 150 bp linking sequences between them, and established an integrated phylogenic analysis method. The results showed that 391 single bases mutations were found in 70 x 150 bp linking sequences alignment among four species. The number of mutation bases between them were greatly exceeded the 1/1000 predicted in the human genome analysis. C/T(T/C) and A/G (G/A) transitions were the major types of single base mutation. The genetic relationship between pig and bovine who are both Artiodactylous is the nearest, the next is human, and the farthest is mouse. The differentiation sequence taken place in four species from the same ancestor is that mouse is the earliest one, and the latter human, and pig and bovine are the latest.
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Filogenia , Animales , Secuencia de Bases , Bovinos , Etiquetas de Secuencia Expresada , Humanos , Ratones , Datos de Secuencia Molecular , PorcinosRESUMEN
A pair of primers was designed according to the sequence of mammal fatty acid binding protein (FABP) gene, then PCR amplified to chicken genome. After the product of PCR was cloned and sequenced, homologous comparison was done among porcine heart fatty acid binding protein gene and porcine adipocyte fatty acid binding protein gene. The result showed that the sequence of chicken FABP gene had 68% and 75% homology with porcine H-FABP and A-FABP gene respectively, and had 75% homology with porcine AFABP on amino acid level. The result of Northern showed that the gene only expressed in fat tissues.
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Tejido Adiposo/metabolismo , Proteínas Portadoras/genética , Miocardio/metabolismo , Proteínas de Neoplasias , Secuencia de Aminoácidos , Animales , Pollos , Clonación Molecular , Proteínas de Unión a Ácidos Grasos , Datos de Secuencia Molecular , Polimorfismo Conformacional Retorcido-Simple , Análisis de Secuencia de ADN/métodos , Homología de Secuencia , PorcinosRESUMEN
In this experiment, F2 chicken derived from Broilers crossing with Silky was used to study the effect of insulin-like growth factor-II gene on growth and carcass traits. The partial gene was amplified by two pairs of primers, and single nucleotide polymorphism (SNPs) was detected by the technique of restriction fragment length polymorphism (RFLP), and then confirmed by DNA sequencing. The mutation was found in the exon-2 of the gene, and can be clarified by cutting of restriction enzyme Aci-I. The result of least square analysis showed the gene was significantly related with growth and carcass traits. It implied that the insulin-like growth factor-II gene could be a genetic locus or linked to a major gene affecting greatly the growth and carcass traits in chicken.
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Factor II del Crecimiento Similar a la Insulina/genética , Polimorfismo de Nucleótido Simple , Carácter Cuantitativo Heredable , Animales , Pollos , Ligamiento Genético , Factor II del Crecimiento Similar a la Insulina/fisiología , Análisis de los Mínimos Cuadrados , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
In animal breeding, microsatellite marker plays an important role in constructing genetic maps, QTL mapping and function analysis of structural genes. Myostatin, also known as GDF8, is a negative regulator of skeletal muscle mass and, in swine, it is evidenced to be related to birth weight and average daily gain from 60 kg to 100 kg of body weight. In present study, by subcloning and sequencing,we identified a novel microsatellite marker which is useful for fine QTL mapping for meat traits. A BAC clone containing porcine MSTN was extracted and digested with EcoR I to recover the fragment of > 4 kb for subcloning in pGEM-3zf (+). Sequencing and alignment results showed that this subcloned fragment was not from porcine MSTN, but included a tandem repeat of (TG) 13, which is a novel microsatellite marker (GenBank accession number: AF454400) flanking MSTN. To exclude its vector origin we designed specific primers flanking this marker and successfully amplified this fragment from porcine genome. Through a pedigree analysis of a double-muscled Yorshire strain, we found that it is inherited in a co-dominant manner. We also checked the gene frequencies of this locus in 381 unrelated individuals of 7 pig breeds, namely Laiwu,Landrace, Yorkshire,Duroc, Peterian, Min and Erhualian. Only two alleles were detected, the repeating number of which are 13 (allele A) and 19 (allele B) respectively, which indicated that it is a low poly morphic microsatellite marker. In addition, the frequencies of the two alleles are different between the two types of pig breeds, while allele A is dominant in Chinese local breeds, allele B is dominant in imported breeds. Alignment with AY208121 indicate that this locus is located 42 kb downstream of porcine MSTN. We speculate that this microsatellite DNA is an important marker both in fine QTL mapping for meat traits and in the expression study of porcine MSTN.
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Repeticiones de Microsatélite , Porcinos/genética , Factor de Crecimiento Transformador beta/genética , Animales , Secuencia de Bases , Cromosomas Artificiales Bacterianos , Frecuencia de los Genes , Datos de Secuencia Molecular , MiostatinaRESUMEN
Combining the technique of multiplex-PCR and the fluorescent semi-automated detection, a large-scale genome scanning was performed for 440 chickens, which was derived from China Agricultural University chicken resource families, within three generations. Fifty-five microsatellite markers were analyzed for this study. Those 55 microsatellite loci accorded with the characters of Mendelian co-inheritance. The heterozygosities ranged from zero to 0.89, with 72% of loci having a heterozygosity of more than 0.60. The polymorphism information content (PIC) ranged from 0 to 0.85, in which 70% of those loci had a PIC of more than 0.50 but their distribution varied in line A and line C. The allele frequency was significantly different between line A and line C at most loci (P < 0.01). At the same time, gene accordance inclination was found in line C. The Nei population resemble coefficient and standard genetic distance were 0.1002 and 0.8928.
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Pollos/genética , Genoma , Animales , Genotipo , Repeticiones de Microsatélite , Reacción en Cadena de la Polimerasa , Polimorfismo GenéticoRESUMEN
Created Restriction Site PCR (CRS-PCR) is a simple and efficient method to identify SNP genotypes. One or more mismatch bases are used in a primer to create a restriction site by combining SNP site after PCR. The CRS-PCR products can be genotyped with a way the same as PCR-RFLP. In the study, Extracellular fatty acid binding protein (EX-FABP) gene was served as an example for establishing the CRS-PCR method. Strategy of CRS-PCR was also discussed.
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Polydactyly is a common abnormal limb phenotype in vertebrate and there is similar limb phenotype among different species. Research shows that polydactyly has a similar development mechanism, and this kind of polydactyly character seems to be controlled by homologous genes among species. The latest research results on human and mouse further shows that PPD should be caused by the disruption of a long range cis-acting regulator for Shh within Lmbr1 intron. Here the development mechanism and related genes controlling polydactyly character of vertebrate are reviewed.
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Proteínas de la Membrana/genética , Polidactilia/genética , Transactivadores/genética , Animales , Cromosomas Humanos Par 2 , Cromosomas Humanos Par 7 , Proteínas Hedgehog , Proteínas de Homeodominio/genética , Humanos , Intrones , Factores de Transcripción de Tipo Kruppel/genética , Proteínas de la Membrana/metabolismo , Mutación , Proteínas del Tejido Nervioso/genética , Fenotipo , Polidactilia/metabolismo , Factores de Transcripción/genética , Proteína Gli3 con Dedos de ZincRESUMEN
The study of the molecular regulation mechanism of melanin synthesis during animal development has become a new focus recently . The synthesis and production of melanin during animal development are regulated by many genes. This paper summarized the molecular function mechanism of melanocortin-1-receptor (MC1R) gene and the relationship between the consequences of polymorphic variation of the gene and melanin traits, in addition to summarized the identification and mutation of MC1R gene in birds. Furthermore, the melanin synthesis mechanism in birds is also discussed here.
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Péptidos y Proteínas de Señalización Intercelular/metabolismo , Melaninas/biosíntesis , Melanocitos/metabolismo , Receptor de Melanocortina Tipo 1/genética , alfa-MSH/metabolismo , Hormona Adrenocorticotrópica/metabolismo , Proteína de Señalización Agouti , Animales , Variación Genética , Color del Cabello/genética , Humanos , Hormonas Estimuladoras de los Melanocitos/antagonistas & inhibidores , Receptor de Melanocortina Tipo 1/metabolismo , Transducción de Señal , Pigmentación de la Piel/genéticaRESUMEN
A whole cell sensor, Pseudomonas fluorescens A506 (pTS), was immobilized by sodium alginate and the factors of cell density, immobilization time and beads usage were optimized. The performance of the immobilized cells was compared with that of the free cells. After 2 h immobilization,the increasing speed of fluorescent signal of immobilized cells was 2.26 times as high as that of the free cells,and the peak value was 2.23 times as high during the detection time ranging from 1.5 to 6.0 h. The constantly lower growth and density of the immobilized cell implied the enhanced signal intensity of single cells after immobilization. Meanwhile, the cell density decreased as the immobilization time prolonged. Cell density and immobilization time were the dominant factors affecting the detection signal. For benzene at higher concentrations, the immobilized biosensor showed more rapid signal response at the early period of detection.